Importing a taxonomy doesn’t update custom taxonomy fields in existing items

First of all, thanks for this very functional plug-in!

I’ve successfully imported a bunch of custom posts, including their linked taxonomies, but including the taxonomy like this doesn’t seem to import the taxonomy’s custom fields. When I import the needed taxonomy on its own I am able to map its custom fields so I tried to update the taxonomy items (that came with the posts) by importing the taxonomy again with the custom fields mapped and choosing to update existing items but nothing gets updated whatever I try. Am I doing something wrong?

Thanks in advance!